Method or process of making artificial teeth.



No. 868,109. PATENTED OCT. 15, 1907.

J. MORRIS. METHOD 0R PROCESS OF MAKING ARTIFIGIAL TEETH.

APPLICATION FILED 8EPT.15.1905.

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JOSEPH MORRIS, OF NORTH WALES, PENNSYLVANIA, ASSIGNOR TO THE DENTALPROTEO TIVE SUPPLY COMPANY OF THE UNITED STATES, OF CHICAGO, ILLINOIS, ACORPORA- TION OF ILLINOIS.

Specification of Letters Patent.

Patented Oct. 15, 1907.

,"rpnlication filed September 15,1905. Serial No. 278,610-

To all whom it may concern:

Be it known that I, .IosEPi-r MORRIS, a citizen of the United States,residing at N orth Wales, in the county of Montgomery and State ofPennsylvania, have invented certain new and useful Improvements inMethods or Processes of Making Artificial Teeth, of which the followingis a specification.

This invention pertains to the manufacture of artificial teeth of thatclass or type which are commonly made of porcelain and are provided withinset pins on the back or reverse side IOI'JRHPOSGS of mechanicalconnection with a plate or bridge, the invention being applicable to themanufacture of both what are known as vulcanite teeth and what are knownas plate or flat back teeth. Porcelain teeth are commonly manufacturedat present by a molding and subsequent burning process, the plasticporcelain forming the front and back halves of the artificial teethbeingdeposited in a pair of mold-plates, which latter are rigidly united withthe mold-cavities in registration, the material being then dried out bya baking heat, which unites the front and rear parts, next removed fromthe mold and the edges thereof trimmed and shaped, and finally subjectedto a fusing heat which thoroughly integrates In these operations, theporcelain forming the rear half of the tooth is, in its plastic state,cast around one or more pins, that serve later to mechanically connectthe tooth to the plate, bridge, or other carrying member. The weak pointin such teeth resides in the character of the anchorage of these pinstherein. Platinum pins afford fairly good results, but are veryexpensive; and hence cheaper composition metal pins are being largelysubstituted. 1t. has been found in practice that when these latter areemployed, while they will withstand the fusing heat to which the toothis finally subjected, yet the heat, through chemical action or from someother cause, produces fine bubbles in the material previously castaround the pins, producing tiny cavities, and weakening the anchorage ofthe pins in the porcelain.

Again, in the ordinary vulcanite tooth, these pins,

when made of black metal, a carbonized nickel at present employed, showthrough the face of the tooth in the form of darkened spots.

The present invention has for its object to provide a new and improvedmethod or process of manufacturing artificial teeth which obviates theobjections above referred to and produces a tooth, whether of thevulcanite or fiat-back variety, in which the pins have a stronger andmore secure anchorage, and in which the discoloration resultant from theuse of black metal pins is avoided.

To these ends, and in accordance with my invention,

I have modified and improved the usual method of manufacture ashereinabove briefly outlined, chiefly in respect to the manner ofanchoring the pins in the back of the tooth.

In accordance with my present invention, and in contradistinction to themethod of casting and molding the body porcelain around the pins, Ifirst cast and mold around the pins a novel composition materialconsisting preferably of porcelain mixed with an oxid or salt of one ormore metals, which composition material affords a secure anchor for thepins, and then over lay this composition material in the mold with thebody porcelain, which is later, in the final burning operation,integrated with the porcelain forming the front or face of the tooth.

In order that my invention may be more readily understood, I haveillustrated in the accompanying drawing a mold for carrying out theprocess, as well as a tooth forming the product of the process; andreferring thereto,Figure 1 is a plan view of the top section of a. moldfor making a tooth; Fig. 2 is a similar view of the bottom section of amold in which the rear half of the tooth is cast and anchored to thepins; Fig. 3 is a rear elevational view of a finished tooth made inaccordance with the method of the present invention; and Fig. 4 is alongitudinal vertical section on the line Referring now more in detailto the novel manner and process of manufacture of artificial teeth inwhich the present invention inlieres, 5 and 6 may designate,respectively, the top and bottom plates or halves ofa mold in which thetooth is formed The mold-plate 5 contains a series of depressions orcavities 7, each of which corresponds in surface contour to the form ofthe outer or face section of a tooth. In each of these cavities isdeposited in a plastic condition a body of powdered porcelain 8, adheredby water and gum tragacanth, which subsequently becomes the enamel frontof the tooth. This material fills the cavity, except at the upperportion thereof, which latter is designed to subsequently have pressedthereinto part of the body porcelain from the opposite half of the mold,to form what is known as the neck of the tooth.

The lower mold-section 6 has a similar series of cavities 9, each havinga pair of holes in its bottom for the reception of pins 1.0 that are tobe embedded in the material cast therein. These cavities are loaded bypressing into the end corresponding to the lower or cutting end of thetooth a mass of plastic porcelain, designated by 11, which extendssomething less than one-half the total length of the cavity. Around thepins 10 is then packed a body of my novel composition consistingpreferably of porcelain and metal oxid or cated at 12 (Fig. 4), andentirely surrounding and 1 embedding the exposed portions of the pinsand extending upwardly toward that portion of the cavity in which theupper end or neck of the tooth is formed. Finally, a plastic charge ofwhat is known as body porcelain is impressed into the remaining unfilledspace of the cavity, completely overlying and covering the compositionmaterial 12, this body porcelain being indicated at 13 and beingsufficient in quantity to fill the slight unfilled space in the cavityof the opposite mold-member when said parts are united and pressedtogether. The two halves of the mold, thus loaded, are laid together,face to face, and registered by pins 14 in one plate, passing throughholes 15 in the other, and are then clamped together in a suitablebrace. The whole is next subjected to a baking heat suflicient tothoroughly dry out the material and cause the several parts of the toothto adhere to each other. Thereupon the mold is opened, and the teeth,having about the hardness and consistency of chalk, are removed, andtheir edges trimmed down to remove burs and fins, The teeth then undergothe final operation, which consists in subjecting them to a high burningheat, which causes the several porcelain portions and the reinforcingcomposition portion to become thoroughly fused and integrated. I findthat the pins 10, when thus set in a composition material, such asspecified, are very firmly anchored therein, while the compositionmaterial itself not only possesses a degree of resistance to breakingstrains greater than the porcelain itself, but adheres to the latterwith even greater strength than that of the porcelain itself. I havefound by thorough tests that a tooth made as above described possessesfully double the strength and resistance to strains tending to break itaway from the fastening pins of the usual solid porcelain teeth.

The reinforcing or anchoring material above mentioned comprisespreferably porcelain mixed with about an equal part of an oxid or saltof one or more metals. The best results which I have thus far attainedhave been produced by a composition of substantially equal parts ofporcelain and aluminium oxid; but good results are obtainable with theoxids of tin, nickle, corundum, zinc, barium and other metals, which maybe used as substitutes for aluminium oxid, 01' with the latter, or witheach other.

A preliminary step of the above described process of manufacture residesin the preparation of the composition material which is introduced toform the anchorage of the pins. In order to give the metal oxid or salt,which forms one of the components of said composition, a qualityenabling it to fuse readily with the powdered porcelain forming theother ingredient, I

preliminarily heat said oxid or salt to a very high temperature befo emixing the same with the porcelain.

I do notherein claim the product of the above described process, as thesame forms the subject-matter of a companion application filedconcurrently herewith, Serial No. 278,611.

I claim:

1. The method of manufacturing artificial teeth which consists inmolding with the porcelain body of a tooth a backing of compositionmaterial containing a metal oxid constituting an anchorage for the usualfastening pins, and then integrating said parts by heat, substantiallyas described.

2. The method of manufacturing artificial teeth which consists insubjecting a metal oxid to a high temperature,

subsequently mixing said oxid with powdered porcelain, and then fusingsaid mixture with the body of a porcelain tooth and around the usualanchoring pins thereof, substantially as described. I

The method of manufacturing artificial teeth which consists in chargingthe cavity of a mold member with a plastic porcelain, erecting in thecavity of a companion mold-member one or more fastening pins, partiallycharging said last-named cavity around said fastening pins with ananchoring material of superior strength to the porcelain and fusiblewith the latter, filling the rest of said cavity with plastic porcelain,uniting the mold-members with said cavities in registration, and fusingsaid parts of the tooth together, substantially as described.

4. The method of manufacturing artificial teeth which consists incharging the cavity of a mold-member with plastic porcelain, erecting inthe cavity of a companion mold-member one or more fastening pins,charging one end of said last-named cavity with plastic porcelain toform in part the backing of the tooth, further partially charging saidlastnamed cavity around said fastening pins with an anchoring materialof mixed porcelain and metal oxid, charging the rest of said cavity withbody porcelain, uniting the mold-members with said cavities inregistration, subjecting the mold to a baking heat, then removing andtrimming the tooth, and finally subjecting it to a heat sufiicient tofuse and integrate the parts, substantially as described.

5. The method of manufacturing artificial teeth which consists insubjecting a metal oxid to a high temperature, mixing said oxid withpowdered porcelain in a plastic state to form an anchoring composition,charging the cavity of a mold-member with plastic porcelain, erecting inthe cavity of a companion mold-member one or more fastening pins,charging one end of said lastnamed cavity with plastic porcelain to formthe backing of the lower end of the tooth, further partially chargingsaid last-named cavity around said fastening pins with said compositionanchoring. material, charging the rest of said cavity with bodyporcelain, uniting the mold-members with said cavities in registration,subjecting the mold to a baking heat, then removing and trimming thetooth, and finally subjecting it to a heat SllfllCieDt to fuse andintegrate said parts, substantially as described.

JOSEPH MORRIS,

Witnesses THOMAS O. PEIRCE, CLARENCE KuNDuimINn.

